BACKGROUND It is unknown whether differences in the quality of breast cancer care among women from racial and ethnic minority groups, the elderly, and rural areas have changed over time across the continuum of care. METHODS The linked Surveillance, Epidemiology, and End Results‐Medicare database identified 22,701 women ages 66–79 years diagnosed with early stage breast cancer from 1992–1999. Multiple breast cancer processes of care were measured, including breast‐conserving surgery, radiation therapy, documentation of estrogen receptor status, surveillance mammography, and a combined measure of “adequate care”. RESULTS African‐American and Hispanic women were significantly less likely to receive adequate care than White women in unadjusted comparisons (54.7% and 58.0% vs. 68.4% for African‐American and Hispanic vs. White women) and adjusted comparisons (adjusted odds ratio [AOR] 0.67; 95% confidence interval [95% CI] 0.59–0.76, and AOR 0.77; 95% CI 0.66–0.90 for African‐American and Hispanic women, respectively). The proportion of Asian/Pacific Islander women receiving adequate care was similar to White women. When considering only women diagnosed with breast cancer from 1997–1999, African‐American women remained less likely than White women to receive adequate care (AOR 0.63; 95% CI 0.50–0.79). Women ages 75–79 years were less likely to receive adequate care compared with women ages 66–69 years (AOR 0.74; 95% CI 0.69–0.80), and women from rural (vs. metropolitan) areas were less likely to receive adequate care (AOR 0.81; 95% CI 0.73–0.89). CONCLUSIONS The quality of breast cancer care is lower among vulnerable populations across the continuum of care, and many of these differences have not improved in more recent years. Cancer 2005. © 2005 American Cancer Society.